1. Field of the Invention
The present invention relates to an electronic camera. More particularly, the present invention relates to an electronic camera which adjusts a reference level of an image signal representing an object scene.
2. Description of the Related Art
According to one example of this type of camera, an imaging surface of a CCD imager has: an optical black area and a dummy area, each of which corresponds to a black image; and an effective pixel area corresponding to an object scene image. Furthermore, the optical black area and the dummy area are adjacent to each other in a raster scanning direction. Moreover, amounts of dark current generated on the imaging surface decrease in the order of the optical black area, the effective pixel area, and the dummy area. A clamp circuit clamps a raw image signal based on electric charges produced on the imaging surface of the CCD imager at a timing to stride over the optical black area and the dummy area in the raster scanning direction. The raw image signal clamped in this way is subsequently subjected to processes, such as color separation, white balance adjustment, and YUV conversion, in a signal processing circuit.
However, in the above-described camera, setting of the signal processing circuit is not adjusted according to the amount of the dark current generated on the imaging surface, and thus, there is a limit to the improvement of quality of an image signal.